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Akustik-Blog

Kategorie: ‘Events’

IHTA at the BauSIM conference in Weimar

22. September 2022 | von

From the 20th to the 22nd September 2022, the BauSIM conference took place. The scientific core topic of the conference is traditionally the energetic simulation in the building sector and offers an ideal discussion forum for experts from science and industry for mutual exchange. The conference is organized by the and IBSPA Germany-Austria, member of the International Building and Performance Simulation Association (IBPSA) This year’s conference introduced a new session on acoustic simulation topics, and our institute was present.

In particular, our Junior Principal Investigator Dr. Josep Llorca-Bofí, from the PAAD group was invited as key-note speaker, talking about The city – A machine for noise? Virtual acoustics in architectural design research. Together with our PhD student M. Sc. Jonas Heck and  Professor Michael Vorländer, the following research paper was presented: 3D photogrammetry for auralization – An approach for geometry simplification and material categorization.

 

junge DEGA Workshop 2022 in Stuttgart

12. September 2022 | von

From 2nd to 4th September 2022, after a three-years break due to the Covid-19 pandemic, the “junge DEGA Herbstworkshop” took place in Stuttgart, like the DAGA conference earlier this year. Junge DEGA is a sub-group of the German Acoustical Society with the mission to connect students, PhDs and young professionals in the domain of acoustics. It organizes special sessions and panel discussions during the Annual German Conference on Acoustics (DAGA), providing information on research funding opportunities and job entry. Furthermore, junge DEGA offers a mentoring program with active participation from industry and academia.

Two PhD students of the Institute for Hearing Technology and Acoustics, Simon Kersten and Jonas Heck, as well as Nils Rummler, recently graduated bachelor student, participated in this year’s workshop. The program started with visits at the Fraunhofer Institute for Building Physics IBP and the Center for Building Physics (ZfB, Hochschule für Technik Stuttgart). Furthermore, it consisted of short presentations given by the participants, a plenary meeting of the junge DEGA group to plan the following year’s activities and a guided visit of the new main station construction site (known as Stuttgart 21) with a focus on noise and vibration control. The weekend was concluded with a hands-on workshop on building a loudspeaker from residual materials and competing for the highest sound pressure level.

Pictures from the workshop can be found in the gallery below.

 

Promotionsprüfung Muhammad Imran, M.Sc.

04. Februar 2022 | von

Am 4. Februar 2022 hat Herr Muhammad Imran seine mündliche Promotionsprüfung erfolgreich abgeschlossen.

Herr Muhammad Imran promovierte über das Thema:

„Virtual Building Acoustics – Auralization with contextual and Interactive Features“

Abstract:

Building acoustics auralization is used to assess the perceptual aspects of sound transmission in built environments to provide the guidelines for architectural constructions and to evaluate the noise effects on humans. These noise effects have a negative influence on daily-life activities and create disturbances in physical and metal work. These disturbances are present within the dwellings and/or might be from outdoor moving transient sound sources. Methods are available for auralization of sound insulation between connected rooms in compliance with the standardized data formats of sound insulation metrics and building structural geometries. However, there still exist certain challenges to be addressed to construct the transfer functions between noise sources and receiver room for indoor situations as well as for the outdoor moving sound sources and to make these sources audible through audio-visual virtual reality systems in real time and interactively. These challenges are due to certain simplifications which are implicit in the formulation on which the sound insulation prediction models are based, such as, diffuse field assumptions, neglecting source characteristics, and source and receiver room acoustics.

This thesis focuses on addressing the present challenges in the traditional sound insulation rendering techniques and establishing an interface between psychoacoustic research and building acoustics in dwellings (especially airborne sound insulation) integrated with audio-visual virtual reality environments. From the technical perspective, improvements are made in sound insulation prediction methods, and corresponding filter construction and rendering techniques for auralization. In the first place, the building elements are considered as multitude of secondary sources rather than taking them as point source radiators and the bending wave patterns are addressed in order to be able to properly construct the transfer functions from source to the receiver room. Secondly, the room acoustical simulations are carried out for both source and receiving rooms to generate transfer functions from source to the source room walls and from radiating receiving room walls to the listener, so that the geometries and absorption might be fit to the properties desired by the user for the spatial impression of the listening rooms. In addition, the transfer functions from radiating walls of the receiving room to listener are designed in such a way that not only indoor sources are handled nevertheless the outdoor moving sources are also addressed.

Some important conditions are associated with virtual building acoustics auralization research platform for advanced studies of noise effects in dwellings which are addressed. The audio files, generally, used in listening tests are arbitrarily manipulated by audio samples without the background of a physical model of the built environments. They must comply with the standardized data formats of sound reduction indices (level differences) and/or sound transmission coefficients. Other data related to building structure such as geometry shall be strictly connected to the architectural design, the building materials and constructions. Otherwise the conclusions of the psychoacoustic experiments have no direct correlation with the architectural design, especially when presented through virtual environments. To achieve this, the auralization framework is extended toward real-time interactive audio-visual technology, i.e. VR technology, in order to be able to introduce more realism and, hence, contextual features into psychoacoustic experiments. The building acoustics framework is validated by taking indoor and outdoor example case studies. Listening experiments close to real-life situations are carried out by using this framework to show that this framework can be used as an alternate to design new test paradigms which help to better analyse and interpret the noise impact in building situations depending on the actual activity such as working, learning, and rest.

Das IHTA gratuliert sehr herzlich!!

Doctoral exam Muhammad Imran, Examination committee: Prof. Dr. Kay Hameyer, Prof. Dr. Michael Vorländer, Prof. Dr. Edwin Reynders, Prof. Dr. Peter Jax

Promotionsprüfung Dipl.-Ing. Ingo Witew

02. Februar 2022 | von

Am 21. Januar 2022 hat Herr Ingo Witew seine mündliche Promotionsprüfung erfolgreich abgeschlossen.

Herr Witew promovierte über das Thema:

„Measurements in room acoustics – Uncertainties and influence of the measurement position“

Abstract:

Regardless of the field, measurements are essential for the validation of theories and for making well-founded decisions. A criterion for the validity and comparability of measured values is their uncertainty. The „Guide to the Expression of Uncertainty in Measurement“ (GUM) provides a standardized framework for determining and interpreting measurement uncertainty. In room acoustic measurements, the application of these rules is not yet widespread. On the one hand, this is due to the fact that well established 2-CH-FFT correlation techniques rely on a complex principle, which is not covered by the classical guide. In addition, the effect of input variables on a measurement can only be determined in individual cases after considerable effort. An example are fluctuations of room acoustic quantities over smallest distances between measurement locations in concert halls. This change of the sound field over the location is sometimes considerable and can only be predicted in relatively simple boundary value problems. This raises the question of the validity and interpretability of room acoustics measurements.

The goal of this thesis is to provide a GUM-compliant discussion of uncertainties in measuring room acoustic single-number quantities. This starts with a structured search of variables that potentially influence the measurement of room impulse responses. In a second step, this uncertainty is propagated through the algorithm for determining room acoustic single-number quantities.

Further emphasis is placed on the investigation of spatial fluctuations of the sound field in auditoria. The influence of an uncertain measurement position on the overall measurement uncertainty is discussed. To reach general conclusions, the relation between changes in the measurement location and the corresponding changes in room acoustics quantities is investigated empirically in extensive measurement series. To this purpose, a measurement apparatus was designed that allows automatic, high-resolution sampling of sound fields over large areas. The collected data sets the foundation to propagate the uncertainty using a Monte Carlo method.

This study shows how precisely a measurement position must be defined to ensure a given uncertainty of room acoustical single-number quantities. The presented methods form a foundation that can be flexibly extended in future investigations to include additional influences on the measurement uncertainty.

Das IHTA gratuliert sehr herzlich!!



Fotos: Josep Llorca-Bofí

Promotionsprüfung Dipl.-Ing. Florian Pausch

03. Dezember 2021 | von

Am 26. November 2021 hat Herr Florian Johannes Pausch seine mündliche Promotionsprüfung erfolgreich abgeschlossen.

Herr Pausch promovierte über das Thema: „Spatial audio reproduction for hearing aid research: System design, evaluation and application“

Abstract:

Listening, understanding and communicating are essential skills for social interaction in everyday life. Hearing loss (HL) may have severe consequences on these skills and affect individuals by hindering language development, learning success and participation in social life already at an early age. Depending on the individual predisposition, those affected are likely to withdraw from socialisation processes and sometimes suffer from compromised mental and general health. However, these consequences are not limited to children but also apply to adults and elderly people, especially those who refuse to acknowledge their HL and appropriate treatment, leading to an increased risk of apathy and depression, as well as memory problems and dementia. Assistive listening devices, such as hearing aids (HAs), represent an effective technical intervention tool capable of partially restoring impaired hearing and helping to overcome the aforementioned consequences of HL. Despite using the latest technology, individuals fitted with HAs often complain about poor performance of their devices, particularly in demanding indoor communication settings with unfavourable room acoustics. To some extent, these performance shortcomings can be attributed to limitations of HA algorithms, which are often designed and tested using simplified laboratory scenarios that may differ substantially from complex real-world situations. This thesis contributes to bridging this gap by exploring the advantages and flexibility of virtual acoustic environments (VAEs) reproduced by state-of-the-art spatial audio reproduction methods adapted for HA research. In order to further approach the overarching goal of ecological validity, the system design has been complemented by real-time implementations and room acoustic simulations, allowing to include listener movements via motion tracking and simulate plausible indoor environments, respectively. The systems are comparatively evaluated based on measurements and perceptual experiments with normal-hearing individuals, demonstrating their applicability in experiments involving normal-hearing participants and participants with HL.  

Doctoral exam Florian Pausch, Prüfungskommission: Zweitgutachterin Prof. Dr. Astrid van Wieringen (KU Leuven), Prof. Dr. Andrei Vescan, Prof. Dr. Dirk Uwe Sauer, Prof. Dr. Janina Fels

 

Doktorprüfung Florian Pausch. Prof. Dr.-Ing. Janina Fels und Dipl.-Ing. Florian Pausch. Foto: Mark Müller-Giebeler

 

Das IHTA gratuliert sehr herzlich!!

Young Professionals Grant at inter-noise 2021

24. September 2021 | von

From August 1st, 2021 until August 5th, 2021, the 50th International Congress and Exposition on Noise Control Engineering (inter-noise 2021) was held in online mode (originally it was planned to take place in Washington, DC).

Our PhD student Christian Dreier participated in this event and presented the paper Sound source modelling by nonnegative matrix factorisation for virtual reality applications. Related to this contribution, he was selected as a winner of the Young Professionals Grant Competition by the Institute of Noise Control Engineering (I-INCE) – congratulations to Christian for this award!

 

 

 

DAGA 2021 – Die Jahrestagung für Akustik

14. August 2021 | von

Nachdem im Jahr 2020 die in Hannover geplante DAGA-Tagung ausfallen musste, wurde die DAGA 2021 in den Monat August geschoben. Die Hoffnung, dass die Pandemie die Tagungsdurchführung nichtmehr beeinflusst, hat sich nicht erfüllt, aber immerhin kann die in Wien, vom 15. August bis zum 18. August 2021, stattfindene Konferenz als Hybrid-Veranstaltung durchgeführt werden, d.h. eine Teilnahme ist sowohl vor Ort, als auch Online möglich. Aufgrund der Anweisung der RWTH Aachen, Dienstreisen soweit es geht zu vermeiden, nehmen alle IHTA-Beschäftigten online an der Tagung teil und verzichten somit auf die Reise nach Wien.

Die Tagung beginnt am Sonntag mit drei Vorkolloquien, die meisten Sitzungen finden jedoch an den drei Haupttagen von Montag bis Mittwoch statt. Insgesamt ist das Institut für Hörtechnik und Akustik an 27 wissenschaftlichen Beiträgen beteiligt (21 Vorträge und 6 Poster).

Vortrag am Montag:

Jonathan Ehret, Lukas Aspöck, Andrea Bönsch, Janina Fels, Torsten W. Kuhlen Speech Source Directivity for Embodied Conversational Agents

Vorträge am Dienstag:

Michael Kohnen, Michael Vorländer Perceptional differences between Transaural, Ambisonics and Amplitude Panning
Christian Dreier, Michael Vorländer Einfluss lokaler Wetterschwankungen auf die psychoakustische Wahrnehmung von Fluglärm
Simon Kersten, Michael Vorländer FEM-Simulation of Bone Conduction in the Human Head: Influence of Geometrical and Material Parameters
Philipp Schäfer, Jonas Stienen, Michael Vorländer An open-source outdoor sound propagation framework with an application to aircraft noise auralization
Marco Berzborn, Jamilla Balint, Michael Vorländer On the Directional Distribution of Decay Constants in a Reverberation Room
Cosima Ermert, Shaima’A Doma, Janina Fels Examining the influence of controlled HRTF-variation on various distance metrics
Hark Braren, Janina Fels Evaluation of a Child-Appropriate Localization Paradigm
Thomas Deutsch, Lukas Vollmer, Janina Fels An Assessment of Spatial Fidelity of Higher-Order Ambisonics Reproduction Using the SCaLAr System
Lukas Vollmer, Janina Fels The Ventriloquist Illusion in Audiovisual Virtual Reality
Shaima’a Doma, Janina Fels Analysis of spatial cue distortion in HRTFs using a simplified head model
Christian Laufs, Andreas Herweg, Karin Loh, Janina Fels Zusammenhang zwischen dem psychoakustischen Parameter Schärfe und dem physiologischen Parameter Hautleitfähigkeit zur Beurteilung extra-auraler Lärmwirkung

Vorträge am Mittwoch:

Mark Müller-Giebeler, Michael Vorländer Inverse Material Determination for Small Porous Absorber Samples
Sven Herrmann, Mark Müller-Giebeler, Michael Vorländer Machine Learning zur Modellierung des Kanteneffekts bei Porösen Absorbern
Elie Abi Raad, Michael Vorländer Transfer function analysis of welding stage models in Ultrasonic Metal Welding
Sabine Schlittmeier, Lukas Aspöck, Janina Fels, Edina Fintor Erinnern eines in Ruhe gehörten Dialogs: Kolokalisierte Sprecher induzieren mehr Höranstrengung als räumlich separierte Sprecher
Janina Fels, Cosima Ermert, Jonathan Ehret, Chinthusa Mohanathasan, Andrea Bönsch, Torsten W. Kuhlen, Sabine Schlittmeier Listening to, and remembering conversations between two talkers: Cognitive research using embodied conversational agents in audiovisual virtual environments
Carolin Reimers, Larissa Leist, Stephan Fremerey, Alexander Raake, Maria Klatte, Janina Fels Examining Auditory Selective Attention in a Classroom Setting using Audiovisual Virtual Reality
Jamilla Balint, Janina Fels Research data management across disciplines in AUDICTIVE
Stephan Fremerey, Carolin Reimers, Larissa Leist, Jan Spilski, Maria Klatte, Janina Fels, Alexander Raake Generation of audiovisual immersive virtual environments to evaluate cognitive performance in classroom type scenarios
Margret Sibylle Engel, Maria Luiza de Ulhôa Carvalho, Janina Fels, William J. Davies Verification of emotional taxonomies on soundscape perception responses

Poster:

Marco Berzborn, Fabian Brinkmann, Simon Kersten, Kai Jurgeit pyfar: Python Packages for Acoustics Research
Anne Heimes, Michael Vorländer A framework to conduct psychoacoustic experiments in virtual reality
Jonas Heck, Josep Llorca-Bofí, Michael Vorländer Hearing Architecture and Seeing Soundscapes: Methodological Approach of Individual Vocabulary Profiling to Evaluate Audiovisual Perception
Lukas Aspöck, Jonathan Ehret, Stefan Baumann, Andrea Bönsch, Christine T. Röhr, Martine Grice, Torsten W. Kuhlen, Janina Fels Prosodic and visual naturalness of dialogs presented by conversational virtual agents
Isabel Schiller, Jan Alber, Lukas Aspöck, Chinthusa Mohanathasan, Linda Wetzel, Sabine Schlittmeier Text-related immersion for varying auditory background scenes
Karin Loh, Julian Burger, Lukas Aspöck, Janina Fels EduRA database: room models based on room acoustic measurements in primary and preschools

Eine Übersicht über alle weiteren Beiträge der Tagung befinden sich in der der DAGA 2021 App.

 

Doctoral Award 2020 for Dr. Josep Llorca-Bofí

25. November 2020 | von

For his excellent PhD thesis, ITA’s postdoctoral researcher Dr. Josep Llorca-Bofí received the Special Doctoral Award 2020 given by the Universitat Politècnica de Catalunya (UPC). The award was presented to him and 30 other doctoral degree holders in a virtual event on November 6th, 2020. In this edition the awards are given to doctoral degree holders who obtained a cum laude distinction for the defence of their thesis in the 2017-2018 academic year.

Josep’s thesis with the title

“The generative, analytic and instructional capacities of sound in architecture:
fundamentals, tools and evaluation of a design methodology“

connects the fields of architecture, acoustics and engineering and is published Open Access.

The ITA team congratulates Josep to this special award!

 

Promotionsprüfung Dipl.-Ing. Lukas Aspöck

17. Juli 2020 | von

Am 10. Juli 2020 hat Herr Lukas Aspöck seine mündliche Promotionsprüfung erfolgreich abgeschlossen.

Herr Aspöck promovierte über das Thema:
„Validation of room acoustic simulation models“

Abstract:

Already in ancient times, the goal existed to design appropriate environments to transport acoustic signals from a sound source to an audience. Strongly connected to this is the interest to understand room acoustic effects and, in the best case, to accurately predict them. This is of particular relevance today in prestigious projects such as the construction of concert halls, but is also of great importance in everyday life, for example in public buildings. Room acoustic simulations based on the concepts of geometric acoustics have been developed for such purposes for more than 50 years and have been extensively investigated. However, there is still insufficient knowledge about the uncertainty and validity of the results of the room acoustic simulations used today. In addition, many highly simplified simulation models are often used without questioning the validity of the results.

In order to offer developers and researchers a possibility to comprehensively validate the results of their room acoustic simulation, a database with eleven different acoustic scenes was developed, documented and published. The scenes cover both simple environments, where individual acoustic effects such as reflection or diffraction are isolated, and complex spatial situations such as a concert hall. In addition to a detailed description and the definition of input data, acoustic measurements were carried out for all scenes, which serve as reference for the simulations.

Furthermore, a study is presented which was designed following the concept of three previously conducted round robin experiments. Here, the simulation results of up to six participants, who were not informed about measurement results in advance, are compared with each other and with the results of the corresponding measurements. The evaluation of the results for the simple scenes reveals various weaknesses of the geometric acoustics, but in the case of the complex scenes it nonetheless shows acceptable results in the medium frequency range. In further investigations it was determined how much room acoustic simulation results deviate from measurements if the user knows the measurement results beforehand and input data of the simulation is adjusted manually or systematically. From these results it can be concluded which deviations from actual, measured values can be expected in the room acoustic simulation of both unknown and known rooms. Furthermore, this work provides a basis for improvements in the field of geometrical acoustics simulation models and with respect to the determination and selection of correct input data for the simulation.

Das ITA gratuliert sehr herzlich!!

Promotionsprüfung Josefa Oberem, M.Sc.

27. Januar 2020 | von

Am 24. Januar 2020 hat FrauJosefa Oberem, M.Sc, ihre mündliche Promotionsprüfung erfolgreich abgeschlossen.

Frau Oberem promovierte über das Thema:
„Examining auditory selective attention: From dichotic towards realistic environments“

Abstract:

The aim of the present thesis is to examine the cognitive control mechanisms underlying auditory selective attention by considering the influence of variables that increase the complexity of an auditory scene. Therefore, technical aspects such as dynamic binaural hearing, room acoustics and head movements as well as those that influence the efficiency of cognitive processing are taken into account. Step-wise a well-established dichotic-listening paradigm is extended into a “realistic” spatial listening paradigm.
Conducted empirical surveys are based on a dichotic-listening paradigm examining the intentional switching of auditory selective attention. Spoken phrases are simultaneously presented by two speakers to participants from two of eight azimuthal positions. The stimuli are phrases that consist of a single digit (1 to 9, excluding 5), in some experiments followed by either the German direction “UP” or “DOWN”. A visual cue indicates the target’s spatial position, prior to auditory stimulus onset. Afterwards, participants are asked to identify whether the target number is arithmetically smaller or greater than five and to categorize the direction. Reaction time and accuracy are performance measures. Differences of performance measures between the repetition of the target’s spatial position and the related switch (switch costs) describe the loss of efficiency associated with redirecting attention from one target’s location to another. To examine whether the irrelevant auditory information is decoded, interference in the processing of task-relevant and task-irrelevant information is created in the paradigm.
To study the binaural effects in the intentional switching of auditory selective attention, the dichotic-listening paradigm is gradually extended towards a binaural-listening paradigm representing complex dynamic acoustic scenes in the present thesis. In order to realize the extension of the paradigm towards a realistic scene various technical methods and tools need to be applied. As the listening paradigm is step-wise broadened towards realistic scenes the technical methods and tools are assessed with respect to the collected empirical results.
Using the binaural-listening paradigm, the ability to intentionally switch auditory selective attention is tested when applying different methods of spatial reproduction. Essential differences between real sources, an individual and a non-individual binaural synthesis reproduced with headphones as well as a binaural synthesis based on Cross-Talk Cancellation are found. This indicates how the loss of individual information reduces the ability to inhibit irrelevant information. Differences in performance measures occur also with regard to the target’s spatial position. Reliable findings on the spatial localization ability are confirmed applying the listening paradigm on the intentional switching of auditory selective attention. As a step towards multi-talker scenarios in realistic environments participants are tested in differently reverberating environments. Switch costs are highly affected by reverberation and the inhibition is also impaired by to be unattended information. Age-related effects are also found when applying the binaural-listening paradigm, indicating difficulties for elderly to suppress processing the distractor’s speech.

Das ITA gratuliert sehr herzlich!!

Promotionskommission, Foto: Gottfried Behler

ACOUCOU: Development of web-based teaching materials for acoustics

05. November 2019 | von

More than one year ago, the polish company KFB Acoustics initiated a Strategic Partnership involving four European universities (KU Leuven, University of Le Mans, University of Zagreb and RWTH Aachen University) and two companies (HEAD Acoustics and KFB Acoustics), funded by the Erasmus+ program of the EU, with the goal to develop ideas and concepts for the implementation and extension of an online teaching portal including various courses on acoustics. This portal, called ACOUCOU, short for Acoustic Courseware, is available on www.acoucou.org and currently contains one course about Vibroacoustics and example materials from the previous project Acoustics for Industry (ACI).

At the end of October, two ITA employees participated in the final meeting in Wroclaw, Poland, where the outcomes of the project and future events related to the ACOUCOU platform were discussed. The most recent event, an interactive session on educational materials in acoustics, which took place at the ICA conference in Aachen, was rated as a great success by all participants and led to new contacts and helped to disseminate the teaching portal.

The project consortium is also happy to announce that additional funding was granted by the EU to fill the teaching portal with more course contents in a three-year project starting in 2020. This project is named Acoustics Knowledge Alliance  (ASKNOW) and is part of the Erasmus+ Knowledge Alliance program.

Follow updates of the ACOUCOU initiative on social media channels: FacebookTwitter Instagram

Rückblick: ICA 2019 / EAA Euroregio / EAA Summer School

30. Oktober 2019 | von

Dieser Artikel erschien im Akustik Jornal der DEGA, Ausgabe Nr. / Oktober 2019.

Die internationale Tagung für Akustik („23rd International Congress on Acoustics“ – ICA 2019) fand vom 9. bis zum 13. September 2019 in Aachen statt und schloss auch den „4th EAA Euroregio“-Kongress mit ein.

Mit insgesamt 1700 Teilnehmenden, darunter 590 „Students“ war die Tagung ein voller Erfolg. In 147 strukturierten Sitzungen wurden ca. 1.300 Tagungsbeiträge als Vorträge und Poster präsentiert.

Am 09.09. wurde die Tagung von den Conference Chairs (Prof. Michael Vorländer und Prof. Janina Fels) feierlich eröffnet, umrahmt durch Musik von Lily Dahab und ihrer Band.

Fünf Plenarvorträge wurden von hochkarätigen Wissenschaftlerinnen und Wissenschaftlern gehalten:

  • Marion Burgess (Sydney, Australien): “Sound and Noise around us“
  • Shrikanth Narayanan (Los Angeles, USA): “Sounds of the human vocal instrument“
  • Christopher Wiebusch & Tim Otto Roth (Aachen/Köln): “Astroparticle Immersive Synthesizer³ or how cosmic ‚ghost particles‘ inspire a novel concept of spatialisation of sound“
  • Jérémie Voix (Montreal, Kanada, Preisträger des ICA Early Career Awards): “The ear at the age of IoT”
  • Maria Heckl (Keele, England): “Thermoacoustic instabilities – physical mechanisms and mathematical modelling”

Neben dem umfangreichen wissenschaftlichen Hauptprogramm gab es diverse zusätzliche Ereignisse, zum Beispiel die Aktivitäten der „EAA Young Acousticians, YAN“ mit der jDEGA und vielen anderen Gruppen des wissenschaftlichen Nachwuchses. Ferner gab es eine Diskussionsrunde zum Thema Wissenschaftskommunikation mit eingeladenen Experten, eine Kontaktbörse mit Industrievertretern zum Thema Karrierewege für den wissenschaftlichen und professionellen Nachwuchs in der Akustik sowie die „5-minute Research Story Competition“, die Mathieu Gaborit (KTH Stockholm) mit einem Beitrag zur Modellierung von geschichteten Absorbern am sehr unterhaltsamen Beispiel von Tiramisu gewonnen hat.

Das Rahmenprogramm der Tagung umfasste ein Orgelkonzert im Aachener Dom mit dem Domorganist Michael Hoppe sowie eine gesellige Abendveranstaltung im Kunstmuseum „Ludwig Forum“, bei der auch eine internationale Jam Session musikalische Akzente setzte. Ebenso wurden verschiedene Exkursionen für die Teilnehmenden gut angenommen (zur Institut für Technische Akustik der RWTH Aachen, zur HEAD acoustics GmbH und zum Institut für Kraftfahrzeuge der RWTH).

Begleitet wurde die Tagung durch eine internationale Ausstellung mit Vertretern aus Industrie und Forschung mit insgesamt 58 Ständen. Die Vertreter an den Ständen berichteten von einem unerwartet großen Interesse des internationalen Publikums.

Vor dem ICA-Kongress fand im belgischen Leuven die „EAA Summer School“ für junge Akustikerinnen und Akustiker mit 114 Teilnehmenden statt, die von Monika Rychtarikova und Armin Kohlrausch organisiert wurde. Vom 6. bis 8. September wurden neben dem Kurs „Introductory Course – Approaching Acoustics” vier “Hot Topics”-Kurse zu “Computational modeling in physiological and psychological acoustics”, “Smart city sound”, “Acoustic metamaterials and sonic crystals” und “Acoustic imaging (laser, beamforming, time reversal, photoacoustics)” angeboten.

Auch die weiteren Satellite-Symposien (EAA Spatial Audio Signal Processing Symposium in Paris, International Symposium on Room Acoustics in Amsterdam, International Symposium on Musical Acoustics in Detmold) wurden von den Teilnehmenden gut angenommen, so dass der Monat September 2019 insgesamt sehr reichhaltig an internationalen Veranstaltungen rund um die Akustik war.

Promotionsprüfung Dipl.-Ing. Jan-Gerrit Richter

25. Februar 2019 | von

Am 22. Februar 2019 hat Herr Dipl.-Ing. Jan-Gerrit Richter seine mündliche Promotionsprüfung erfolgreich abgeschlossen.

Herr Richter promovierte über das Thema:

„Fast Measurement of Individual Head-Related Transfer Functions“

Abstract:

Sogenannte Außenohrübertragungsfunktionen (engl. Head-Related Transfer Functions, HRTFs) werden genutzt, um virtuelle Schallquellen an beliebigen räumlichen Positionen zu erzeugen. Dieses Verfahren, die binaurale Synthese, ist Grundlage für die physikalisch korrekte Wiedergabe von simulierten akustischen Szenen jeglicher Art. Die HRTFs beschreiben den Einfluss von Kopf, Torso und Pinna auf das Schallfeld. Hierbei werden sowohl Zeit- als auch Frequenzeinflüsse zwischen den Ohren erfasst, welche jedoch von der Einfallsrichtung des Schalls abhängig sind. Die HRTF besitzt also zusätzlich zu einer Frequenzabhängigkeit auch eine hohe Abhängigkeit hinsichtlich der Quellposition. Mittels moderner Messaufbauten sind Messungen mit hochpräziser räumlicher Auflösung möglich, welche jedoch bis zu 5 Stunden für eine den Kopf umschließender Sphäre in Anspruch nehmen. Diese lange Messdauer bei den klassischen Verfahren schließt individuelle Messungen an menschlichen Probanden aus.
In dieser Arbeit wird ein Messsystem evaluiert und optimiert, welches individuelle Messung in einer kurzen Dauer mit hoher räumlicher Auflösung ermöglich. Mit Hilfe dieses Systems kann die Messzeit für eine Messung mit räumlicher Auflösung von 5° in Azimuth and 2.5° in Elevation von 5 Stunden auf 7 Minuten reduziert werden.Der erste Teil der Arbeit beschreibt die Evaluierung der Qualität der Messungen. Zu diesem Zweck werden objektive Fehlermaße definiert, welche Unterschiede zu einer Referenzmessung zu einem frequenzabhängigen Maß zusammenfassen. Aus diesem Maß werden Messfehler an verschiedener Objekte mit unterschiedlicher räumlicher Komplexität evaluiert welche mit Messungen aus etablierten Systemen, sowie analytische Lösungen und Simulationen verglichen werden. Das Ziel ist es, die vom Messsystem verursachten Störungen frequenzabhängig zu erkennen und zu bewerten. Eine subjektive Evaluierung der Qualität der gemessenen HRTFs wird hinsichtlich der Lokalisationsgenauigkeit von virtuellen Quellen, welche HRTFs aus schnellen Messungen und einer Referenzmessung verwenden, durchgeführt. Der Vergleich aus HRTFs einer schnellen Messung und einer Messung mithilfe eines etablierten Systems zeigt keinen signifikanter Einfluss des schnellen Messsystems auf die Lokalisationsgenauigkeit. Zusätzlich wird die Lokalisationsgenauigkeit mit individuellen HRTFs in weiteren Versuchen getestet. Die Ergebnisse, welche zur Evaluierung mit Werten aus der Literatur verglichen  werden, legen keine Beeinträchtigung der HRTFs durch die schnelle Messung nahe.
Um die Messzeit weiter zu reduzieren, wird die Messung in einem weiteren Schritt um sogenannte kontinuierlicher Drehung erweitert. Hierzu wird eine Methode zur Kompensation dieser Drehung während der Messung entwickelt. Dieses Verfahren wird sowohl objektiv und subjektiv evaluiert, um die schnellste Drehgeschwindigkeit, bei der keine hörbaren Artefakte in den reproduzierten Signalen erzeugen werden, zu ermitteln. Die Evaluierungen zeigen, dass mit dieser Messmethode die Messdauer bei einer typischen räumlichen Auflösung von 5° in Azimuth and 2.5° in Elevation zusätzlich um ca. 350% auf etwa 2 Minuten verkürzt werden kann.
Das hierzu vorgestellte Korrekturverfahren wird im letzten Kapitel der Arbeit erweitert, um den Einfluss von Probandenbewegung während der Messung zu kompensieren. Diese Bewegungen werden seit langem als wichtiger Störfaktor bei individuellen Messungen angesehen. In einer Studie wird zunächst untersucht, wie viel sich Probanden während der Messung bewegen. Hierbei wird verglichen, wie groß Unterschiede zwischen sitzenden oder stehenden Probanden und der Einfluss der Probandendrehung ist. Zusätzlich wird ein Feedback System entworfen, mit welchem die Probanden während der Messung selbst die Möglichkeit haben, ihre Position zu korrigieren. Die Grenzen der Bewegungskompensation werden mit Hilfe eines Kunstkopfes, der kontrolliert während der Messung bewegt wird, für einen Freiheitsgrad der Orientierung evaluiert. Die vorgestellte Kompensation ist in der Lage, jeglichen Fehler aus der Bewegung auf das Niveau von Messunsicherheiten zu reduzieren.

Das ITA gratuliert sehr herzlich!!

GfTA Studienpreise 2018 für Jonas Förster und Saskia Wepner

17. Dezember 2018 | von
Auch in diesem Jahr wurde von der Gesellschaft für Technische Akustik e.V. (GfTA) je ein Preis für eine herausragende Bachelorarbeit und eine herausragende Masterarbeit vergeben. Die Preisträger wurden im Rahmen der ITA Weihnachtsfeier gekürt, und wir sagen natürlich herzlichen Glückwunsch Jonas Förster und Saskia Wepner!

Foto: Florian Pausch

Foto: Florian Pausch

Das ITA bei den „Highlights der Physik“ in Dortmund

23. Oktober 2018 | von

Nach einer mehrjährigen Pause war das Institut für Technische Akustik im Jahr 2018 wieder bei den „Highlights der Physik“ vertreten.  Mit dieser Veranstaltungsreihe möchte das Bundesministerium für Bildung und Forschung (BMBF) die Öffentlichkeit, insbesondere Schülerinnen und Schüler, mehr für die zahlreichen Themenbereich der Physik begeistern. Gastgeber und Mitorganisatoren der Veranstaltung in diesem Jahr waren die Stadt Dortmund sowie die Technische Universität Dortmund, die sich in den Projekttagen vom 17.9.2018 bis zum 22.09.2018 über rund 48.000 Besucher an den vielen Ständen und Vorträgen freuten.

Das ITA war mit einem Stand zum Thema „Mit zwei Ohren hört man besser“ durch den Mitarbeiter Philipp Schäfer sowie durch die studentischen Mitarbeiter Philipp Eschbach und Pascal Palenda vertreten, welche interessierten Besucher die Grundlagen und aktuelle Forschungsfragen im Bereich des binauralen Hören und der Raumakustiksimulation anschaulich demonstrieren.

Die offizielle Pressemitteilung des Veranstalters finden Sie hier. Vielen Dank an Dr. Axel Carl für die hervorragende Organisation und an die Fotografen von Offer & Offer für die Bereitstellung ihrer Fotos.